[polytely]

While true, Snowden position as administrator placed him outside the usual compartmentalization (because he worked on connecting separate parts of the infrastructure)[0], and placed him in a unique position to realize what was happening and to exfiltrate the proof. I suspect most of the other people who knew the whole picture, were a lot higher up the food chain.

[0]: see his appearance on the Joe Rogan podcast (it's really long and rambly but there are some fun nuggets in there) Snowdens book might be a better source but I haven't read it yet.